^°i9?2^'] SHUFELDT, Skeleton of U 'edge-tailed Ecuile. 301 



faintly indicated in the cranium of that bird from the Melbourne 

 Museum; further, they are (|uite evident in the skull of the 

 White-headed Eagle (No. 19926). There is not the slightest 

 indication of them in the skulls at hand of the Kamchatkan 

 Eagle or in Fithecophaga. However, in view of the fact that 

 they are present in one skull of Uroaettis and not in another — 

 both skulls being from adult individuals — it would seem that the 

 feature should carry but little weight as a classificatory 

 character. 



Turning to the mandible (PI. i., Figs. 1, 2; I'l. iii., Fig. 6), 

 we Jfind that the characters it presents in no way diil'c! from 

 what I have described for Eagles in other places. § 



Some Eagles have the interramal angle more acute than others, 

 even in individuals of the same species, as is the case vvith the 

 jaws of the two Wedge-tails at hand. The depth of the 

 smyphysis also varies; but these are merely individual variations 

 that occur in all animals of the same species. Our Golden Eagle 

 has the rami of the mandible very shallow; it is somewhat deeper 

 in the White-headed Eagle ; proportionately still deeper in the 

 Kamchatkan bird, and, relatively a;^ well as actually, deepest of 

 all in the Wedge-tail. All Eagles possess a more or less massive 

 mandible, in which no splenial z'acuity ever exists. 



The bones of the tongue (hyoidean arches) in our subject 

 present no characters beyond what we meet with in all true 

 Eagles (PI. iii.. Fig. 6), with the few usual variations, either 

 indi\idual or specific. 



Already I have stated, in my article on the osteology of Pithe- 

 copJiaga, that "in many publications here and abroad I have de- 

 scribed the skeletons of various species of Eagles, Falcons, 

 Hawks, and their near congeners, both fossil and existing forms, 

 and it may be said that we meet with few marked differences 

 in any of them with respect to the characters presented on the 

 part of the hyoidean arches or skeletons of the lingual ajjparatus 

 CPl. iii.. Fig. 10)." 



A noteworthy dej)arture in the case of the tongue-bones is to 

 be seen in the Kamchatkan Eagle. In that giant Eagle we find 

 the glosso-hyal extensively ossified at its basal extremity, where 

 it assumes the form of a capital letter H, as it does in some of 

 the lesser Falconidcr — in Circus, for example ; a figure of the 

 hyoid bones in that species may be seen in mv "Osteology of 

 Birds" (P. 56, Fig. 22). ' 



SKELETON OF THE TRUNK. 



Where we find, in birds of the same sub- family and more or 

 less nearly related genera, their skulls and associated bones very 

 much alike with respect to their characters, it is fair to presume 

 that the same will obtain with respect to the vertebrae, ribs, pec- 



§ See bibliographj' of my publications on the osteology cf eagles in the 

 above cited brochure on Pithrcophaga. ■* 



